Typically, an electrical system includes electronic components that communicate with one another to perform system functions. The components can be analog or digital components or a combination of analog and digital components in a mixed signal system. The components can be situated on the same integrated circuit chip or on different integrated circuit chips.
Usually, sensor chips include both analog and digital components. The sensors can be any suitable sensors, such as optical sensors, inductive sensors, capacitive sensors, resistive sensors, and magnetic sensors that measure magnetic flux and/or the strength and direction of a magnetic field. The sensors are used in many applications, including scientific, navigational, industrial and automotive applications.
Magnetic sensors use several types of sensing technologies, including Hall effect sensing technologies and magneto-resistive (XMR) sensing technologies. Hall effect sensing elements convert the energy stored in a magnetic field to an electrical signal by developing a voltage between the two edges of a current-carrying conductor whose faces are perpendicular to the magnetic field. XMR sensing elements measure electrical resistance as a function of the applied or ambient magnetic field. XMR sensing elements include anisotropic magneto-resistive (AMR) sensing elements, giant magneto-resistive (GMR) sensing elements, tunneling magneto-resistive (TMR) sensing elements and colossal magneto-resistive (CMR) sensing elements.
In industries, such as the automobile industry, customers drive product quality and safety requirements. Manufacturers strive to reach zero defect manufacturing goals and safety goals, such as Safety Integrity Level (SIL) goals. For sensors, one objective is to detect and report malfunctioning sensors.
Typically, digital components are tested via testing procedures, such as boundary scan testing and IDDQ testing. The digital components can be tested before assembling the system and after assembling the system. Also, the digital components can be tested in the application via watchdog techniques to ensure proper operation of the digital components.
Analog components, however, are often only tested individually before assembling the system. Testing the analog components after assembling the system and/or in the application may be possible, but it adds cost to the system.
For these and other reasons there is a need for the present invention.